Re: Sloped Top Issues
Hi Travis,
For my first project, I sure did add a few complex tricks.. And at each step, I had to figure out "how" to do it. The sloped tops are done right. As well, I added a interchangeable faceplate, so that I can try different drivers, of different sizes, without altering the cabinet afterward.. and I thought of making different face plates to match these drivers... and adding a hole at the back (covered with a plate) so that I can add a second driver at the back to make it dipole.. and I .. anyway, I'll soon put pics of it.. Let's just hope they're fun to listen to.
How do you like your own Zigmas?
tleonard said:
Hi Travis,
For my first project, I sure did add a few complex tricks.. And at each step, I had to figure out "how" to do it. The sloped tops are done right. As well, I added a interchangeable faceplate, so that I can try different drivers, of different sizes, without altering the cabinet afterward.. and I thought of making different face plates to match these drivers... and adding a hole at the back (covered with a plate) so that I can add a second driver at the back to make it dipole.. and I .. anyway, I'll soon put pics of it.. Let's just hope they're fun to listen to.
How do you like your own Zigmas?
You'd need to double the effective size of these if you're going to use two drivers in biole (or any) configuration as I understand it. I could be wrong though, and it will be interesting to see what gives at any rate. Not a bad idea though -I'll have to give it a try at some point. Good luck!
Best
Scott.
Best
Scott.
theory
Well, I am just a beginer, and alas, have not much theory.. Just trying so see what makes what, and then try to explain it.
So, I made my enclosures so that I can put the Fosters in it, then try the Philips, and as well, put back the Fosters but in "bipole" configuration.
I'm almost there, just need to fnish some details, and I'm ready to go.
Well, I am just a beginer, and alas, have not much theory.. Just trying so see what makes what, and then try to explain it.
So, I made my enclosures so that I can put the Fosters in it, then try the Philips, and as well, put back the Fosters but in "bipole" configuration.
I'm almost there, just need to fnish some details, and I'm ready to go.
What is Mass-Loading? Oh dear, a technical question! Read this (and the rest of Martin's site):
http://www.quarter-wave.com/Project02/ML_TQWT.pdf
All will be revealed. Probably. If you can wade through the math -Martin is very obviously a latant mathematical genius. Still, that's what it took to crack the mysteries of the TL. You can still build this superb project BTW using the FE167E. I've built two pairs so far, and may build a third quite soon.
Short version: in practical terms mass-loading involves stuffing strategies, or lining the cabinet, as Bob Brines generally does now with his designs. This added mass loads the quarter-wavelength standing waves generated in a transmission lines' cabinet. Also, with straight ML TL and ML TQWT designs, a port of some form is usually employed: this adds additional air mass to the loading on the quarter-waves thanks to the restriction provided by the port.
Best
Scott
http://www.quarter-wave.com/Project02/ML_TQWT.pdf
All will be revealed. Probably. If you can wade through the math -Martin is very obviously a latant mathematical genius. Still, that's what it took to crack the mysteries of the TL. You can still build this superb project BTW using the FE167E. I've built two pairs so far, and may build a third quite soon.
Short version: in practical terms mass-loading involves stuffing strategies, or lining the cabinet, as Bob Brines generally does now with his designs. This added mass loads the quarter-wavelength standing waves generated in a transmission lines' cabinet. Also, with straight ML TL and ML TQWT designs, a port of some form is usually employed: this adds additional air mass to the loading on the quarter-waves thanks to the restriction provided by the port.
Best
Scott
Scottmoose said:
Is the Zigmahornet a TQWT? or a TL? or just some kind of tuned pipe? and then, should it be "mass loaded" furthermore by adding stuffing?
By the way, I started reading the doc you refered to, and it's quite interesting. It's sunny and hot here (at last) so, reading will have to wait a bit, but I'll be back to it soon..
Glad you've found the documentation useful.
As for the Zigma, I had trouble deciding what it is myself, so you're not alone! My guess, confirmed by Dave, is that it's a straight, mass-loaded design. The mass loading in the case of the Zigma in my experience only requires a 1in layer of felt etc attached to the sloped top. The models I've run recently suggest, this slope actually doesn't make a huge difference to the sound.
Best (& enjoy the sun!)
Scott
As for the Zigma, I had trouble deciding what it is myself, so you're not alone! My guess, confirmed by Dave, is that it's a straight, mass-loaded design. The mass loading in the case of the Zigma in my experience only requires a 1in layer of felt etc attached to the sloped top. The models I've run recently suggest, this slope actually doesn't make a huge difference to the sound.
Best (& enjoy the sun!)
Scott
Sylver300B said:
With King & Augspurger allowing us to explore much more of quarter-wave space, the pigieon holes we have used are starting to become blurred. A TQWT (aka TQWP, Voigt Pipe) is a QW design that is larger at the terminus end than at the closed end and has linear taper. A TL is smaller (or the same) at the terminus & larger at the closed end. But to make things a bit trickier the whole space can be referred to at times as pipes, or TLs.
The Zigmahornet is an ML-TL. It is the restricted terminus (aks port) that provides the mass loading. As well as providing mass it also adds a pole to the high frequency output of the terminus, meaning that less stuffing can be used to kill the undesired line harmonics, typically resulting in more LF gain at the terminus.
Stuffing has nothing to do with mass-loading, its purpose is to provide a LP function at the terminus
dave
I tend to view mass-loading as the air in the cabinet in general, with the restricted area of a port providing an additional load. Stuffing / lining damps higher harmonics in the mass-loaded line, which 9 times out of 10 this technique requires to smooth out the frequency response. My description before didn't make that clear (I really should have woken up before writing!)
Cheers
Scott
Cheers
Scott
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